Effect of heat treatments on fatigue property of selective laser melting AlSi10Mg

The fatigue property of selective laser melting AlSi10Mg samples with different heat treatments was investigated. The samples were tested in the state of as-built condition, stress relief treatment, solution treatment and solution + artificial aging treatment. It is found that the as-built sample displays the highest fatigue property, and the solution treatment samples exhibit the lowest fatigue property. Heat treatment reduces the fatigue property. The fatigue cracks originate from the surface or subsurface of all the samples, surface or subsurface pores have quite important effect on fatigue property. It is found that the fatigue property is closely related to the yield strength other than ultimate tensile strength or elongation. The change in fatigue property and static mechanical properties is mainly due to the microstructural transformation. Heat treatment changes the size and morphology of Si, which leads to a decrease in fatigue property.